/*
 * Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <assert.h>
#include <delay_timer.h>
#include <platform_def.h>

/***********************************************************
 * The delay timer implementation
 ***********************************************************/
static const timer_ops_t *ops;

/***********************************************************
 * Delay for the given number of microseconds. The driver must
 * be initialized before calling this function.
 ***********************************************************/
void udelay(uint32_t usec)
{
    assert(ops != NULL &&
        (ops->clk_mult != 0) &&
        (ops->clk_div != 0) &&
        (ops->get_timer_value != NULL));

    uint32_t start, delta, total_delta;

    assert(usec < UINT32_MAX / ops->clk_div);

    start = ops->get_timer_value();

    total_delta = (usec * ops->clk_div) / ops->clk_mult;

    do {
        /*
         * If the timer value wraps around, the subtraction will
         * overflow and it will still give the correct result.
         */
        delta = start - ops->get_timer_value(); /* Decreasing counter */

    } while (delta < total_delta);
}

/***********************************************************
 * Delay for the given number of milliseconds. The driver must
 * be initialized before calling this function.
 ***********************************************************/
void mdelay(uint32_t msec)
{
    udelay(msec*1000);
}

/***********************************************************
 * Initialize the timer. The fields in the provided timer
 * ops pointer must be valid.
 ***********************************************************/
void timer_init(const timer_ops_t *ops_ptr)
{
    assert(ops_ptr != NULL  &&
        (ops_ptr->clk_mult != 0) &&
        (ops_ptr->clk_div != 0) &&
        (ops_ptr->get_timer_value != NULL));

    ops = ops_ptr;
}

uint32_t get_timer(uint32_t base)
{
    assert(ops != NULL &&
        (ops->clk_mult != 0) &&
        (ops->clk_div != 0) &&
        (ops->get_timer_value != NULL));

    if (base == 0)
        return ops->get_timer_value();
    else
        return (base - ops->get_timer_value()) * ops->clk_mult / ops->clk_div / 1000;  // for high resolution - xun / 1000; // ms
}

